# Accidental

Source: https://arcosounds.com/glossary/accidental

**An accidental is a sharp, flat, or natural sign placed before a note to raise, lower, or restore its pitch for the remainder of that bar.**

A sharp raises a note a half step, a flat lowers it a half step, and a natural cancels either, returning to the unaltered pitch. Double sharps and double flats raise or lower by a whole step and appear where the harmony requires them. Crucially, an accidental applies to the rest of the bar at that pitch and octave, then expires at the bar line.

A courtesy or cautionary accidental, often in parentheses, restates the key signature's pitch after an accidental has expired, purely to reassure the reader. It changes nothing but prevents hesitation.

Canonical source: https://arcosounds.com/glossary/accidental